Flexible Light Source Unit Non-Linear Locking Edges
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Solution Overview
Problem
Conventional light source units are prone to conduction failures due to stress concentration at the mounting portions of LEDs, leading to cracks and separation of solder from the flexible substrate, resulting in electrical disconnection.
Innovation Solution
A light source unit design featuring a flexible insulating support layer with non-linear locking edges on the opening edges of the cover layer, which interlock with solder portions to distribute stress and prevent separation, ensuring secure electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight line edges are used in the cover layer openings, then the manufacturing process is simple, but stress concentration occurs at the mounting portions leading to conduction failures
Solution Approach 1:
The patent applies curvature by forming the opening edges with non-linear shapes including arc-shaped sections, pointed sections, and wave-like sections instead of straight lines. This curvature design prevents stress concentration at the mounting portions while maintaining manufacturing feasibility through standard PCB fabrication processes.
Solution Approach 2:
The patent introduces asymmetry by making the opening edges have non-uniform shapes with varying curvature radii and configurations. Each opening edge can have different shapes (arc-shaped, pointed, wave-like) to optimize stress distribution at different locations, preventing uniform stress concentration that would occur with symmetric straight-line designs.
2Strength
If the cover layer is made rigid to protect the wiring, then protection is improved, but flexibility is reduced causing stress concentration
Solution Approach 1:
The patent employs a flexible cover layer made of thin film material that can bend and deform without breaking. This flexible structure maintains protection for the underlying wiring while adapting to substrate deformation, preventing stress concentration that would occur with rigid cover layers.
Solution Approach 2:
The non-linear curved edges of the openings in the flexible cover layer allow it to deform smoothly during substrate bending. The curved geometry distributes stress more evenly compared to sharp corners, maintaining both protection and flexibility.
Data Source
AI summary
A light source unit includes light sources and a light source substrate. Each of the light sources includes terminals. The light source substrate includes a support layer, a wiring portion, mounting portions, an insulating cover layer, locking edges, and solder portions. The support layer has flexibility and an insulating property. The wiring portion is formed on the support layer. Each of the mounting portions includes lands provided midway in the wiring portion and facing each other at a distance. The mounting portions are assigned to the light sources, respectively. The insulating cover layer is formed on the support layer to cover the wiring portion and includes opening edges. The locking edges are formed by sections of the opening edges to overlap the lands in a non-linear manner in a plan view. The solder portions conform and adhere to the locking edges and electrically connect the lands to the terminals.